Preparation and spectroscopic properties of chlorofullerenes C60Cl24, C60Cl28, and C60Cl30

We report easy preparation of recently discovered highly chlorinated fullerenes Th–C60Cl24, C1–C60Cl28, and D3d–C60Cl30 in high-temperature reactions of C60 with PCl5 and ICl. Formation and interconversion of chlorofullerenes was investigated in details for C60–ICl system. C60Cl28 is the least stable chlorofullerene that undergoes rearrangement (accompanied by partial chlorine elimination) into more stable Th-C60Cl24 under more drastic reaction conditions (increased temperature and time of chlorination). Th-C60Cl24 yields D3d–C60Cl30 at temperatures above 220 °C via a sequence of rearrangements and further addition of chlorine. In contrast to the fullerene reaction with ICl, interaction of C60 with PCl5 is very selective with respect to formation of C60Cl24 in a wide temperature range. Solid-state electronic (UV–Vis) and vibrational (IR) spectra of chlorinated fullerenes C60Cl24, C60Cl28, C60Cl30 and fluorinated fullerenes C60F18 and C60F36 were recorded in the spectral range between 30 and 45,000 cm−1. Raman spectra were also acquired for all investigated compounds. Moreover, molecular geometry of the C60Cl24 and its theoretical IR-absorption spectrum were calculated using B3LYP/STO-3G chemistry model.